Question: Which of the following numbers is a factor of 99? ${2,3,6,10,14}$
Explanation: By definition, a factor of a number will divide evenly into that number. We can start by dividing $99$ by each of our answer choices. $99 \div 2 = 49\text{ R }1$ $99 \div 3 = 33$ $99 \div 6 = 16\text{ R }3$ $99 \div 10 = 9\text{ R }9$ $99 \div 14 = 7\text{ R }1$ The only answer choice that divides into $99$ with no remainder is $3$ $ 33$ $3$ $99$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $3$ are contained within the prime factors of $99$ $99 = 3\times3\times11 3 = 3$ Therefore the only factor of $99$ out of our choices is $3$. We can say that $99$ is divisible by $3$.